Electrochemical hydrogen evolves both in the cathodic process of corrosion on the interface aqueous solution of electrolyte / Me (steel) and in the cathodic processes of Me (Zn, Cd, Ni, Cr, Sn, Cu, etc) electrodeposition for steel corrosion protection. Absorption of the part of cathodic discharged hydrogen deteriorates all mechanical properties of metal and results in hydrogen embrittlement. During the last three decades, many works on research of systems H-Me have been published and the new materials extremely sensitive to hydrogen fragility have appeared. This new and important book reviews research results concerning the influence of organic brightening compounds on steel hydrogen embrittlement at electrodeposition of the above mentioned metals.